Abstract: In the present study, maltose-binding protein/cholera toxin B subunit/enhanced green fluorescent protein (MBP-CTB-EGFP) complex was constructed by the recombination of MBP, CTB and EGFP, expressed by E. coli and purified. To assess the viability of the recombinant protein as a novel mucosal adjuvant, a cell model was used to explore the ability of MBP-CTB-EGFP to penetrate the cell membrane. Further, the shrimp allergen tropomyosin (TM) was used to produce the recombinant fusion protein MBP-CTB-TM, and we investigated whether it could reduce allergen usage and improve modeling efficiency in food allergy studies. Therefore, MBP-CTB-TM was applied to sensitize Balb/c mice to investigate the allergenicity of the fusion protein, and to evaluate its influence on the food allergy-related immune reactions. The results showed that MBP-CTB-EGFP was able to act as a mucosal adjuvant in promoting the transportation of foreign proteins into cells, and the efficiency was higher than that of transfection. Furthermore, sensitization of mice with the fusion protein MBP-CTB-TM resulted in an OD450 nm of 0.4 for TM specific IgE in ELISA, while the OD450 nm for natural TM sensitization group was only 0.05. In addition, fusion protein sensitization also promoted TM specific IgG1 and IgG2a production. This study shows that the fusion protein MBP-CTB-TM has a better sensitization effect and thus may reduce the requirement for allergens, therefore providing a powerful tool for further allergy studies.

Key words: cholera toxin B subunit, tropomyosin, fusion protein, food allergy, mouse model